(CNN) -- A New Orleans grand jury that declined to indict a doctor on charges that she murdered patients in the chaotic days after Hurricane Katrina never heard testimony from five medical experts brought in by the state to analyze the deaths.

Memorial Medical Center had to be evacuated after floodwaters flowed through New Orleans in 2005.

All five concluded that as many as nine patients were victims of homicide.

In detailed, written statements, the five specialists -- whose expertise includes forensic medicine, medical ethics and palliative care -- determined that patients at Memorial Medical Center had been deliberately killed with overdoses of drugs after Katrina struck New Orleans in 2005.

The grand jury had been asked to consider second-degree murder charges against a doctor and two nurses in four deaths. But in July, the grand jury decided that no one should be indicted.

A grand jury is charged with determining whether there is sufficient evidence to indict a defendant and pursue a trial. The grand jury's proceedings are held in secret, and grand jurors and officers of the court are typically prohibited from divulging what goes on in grand jury sessions.

In a decision that puzzled the five experts hired by the state, New Orleans District Attorney Eddie Jordan never called them to testify before the grand jury. What remains unclear, because of grand jury secrecy laws, is whether the grand jury even saw the experts' written reports. Watch one expert say he doesn't think the grand jury saw his report »

"They weren't interested in presenting those facts to the grand jury," said Dr. Cyril Wecht, the former coroner of Allegheny County, Pennsylvania, and a past president of the American Academy of Forensic Scientists.

"The hard scientific facts are those from five leading experts, [the patients died] from massive lethal doses of morphine and Versed. As far as I know the toxicological findings were not presented to the grand jury and certainly not with quantitative analysis."

Deplorable conditions at medical center

While the grand jury considered charges in four hospital patients' deaths, the medical experts' reports reveal that investigators believed as many as nine patients were victims of homicide. The documents were released after CNN filed a public records request. Read the documents (pdf)

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The probe into the deaths of patients at Memorial Medical Center began after witnesses alleged that seriously ill, mostly elderly patients had been euthanized by medical staff as floodwaters rose around Memorial and conditions inside the building became nearly intolerable.

Those originally arrested in the investigation have denied any wrongdoing, and their lawyers have said they should be applauded for staying with patients as conditions inside the hospital worsened.

One of the physicians absolved in the proceedings, Dr. Anna Pou, described post-Katrina conditions at the hospital as "less than Third World." Hospital staff went into "reverse triage," in which the sickest patients would be treated last, Pou told Newsweek in an article published Saturday.

In the interview, she acknowledges sedating the sickest patients -- not to kill them, she said, but to alleviate their pain until medical personnel could treat them properly.

'I think a lot of people are perplexed'

Louisiana Attorney General Charles Foti also questions why Jordan did not call the five experts before the grand jury. Foti's office conducted the investigation before turning over the evidence to Jordan.

"We're perplexed. I think a lot of people are perplexed," Kris Wartelle, a spokeswoman for Foti, said.

"Those victims' loved ones are asking what happened. They want to know what happened. I think our concern has always been and always will be about them. Nine people died, according to one of the experts, in a three-hour period; one of the experts called that beyond coincidence," she said.

Arthur Caplan, the chair of the Department of Medical Ethics and director of the Center for Bioethics at the University of Pennsylvania, said it's inconceivable that the case is not going to go to trial.

"I was never called to the grand jury," said Caplan. "As far as I know, the grand jury never saw my reports. As far as I know, none of the reports prepared by these experts, who looked at all the cases, who were independent, and came to the conclusion that massive amounts of drugs were used as the cause of death and that they couldn't have been requested [by the patients], they had to be given involuntarily. That's evidence that I think a grand jury would want to be familiar with before it made its decision as to whether or not to proceed with an indictment.

"Now you can still get into a dispute about the evidence," Caplan added. "You can get into a dispute about the circumstances and all the rest of it, but at face value there is no other conclusion I think that's possible, other than these people -- or someone -- killed them."

District attorney says insufficient evidence

Last year, Foti ordered the arrests of Pou and two nurses, Lori Budo and Cheri Landry, on preliminary charges of second-degree murder in the deaths of four of the patients.

Jordan -- who under Louisiana law was responsible for presenting the case to the grand jury -- gave Budo and Landry immunity, in effect ending the state case against them, in exchange for their testimony.

Jordan has refused repeated requests for an interview to discuss his actions in the case. Last week, he sent an e-mail in response to a question about why he had not called the five experts to testify.

"It is inappropriate to disclose what the grand jury did or did not consider," said the e-mail. "The Orleans Parish grand jury concluded that there was insufficient evidence to indict Dr. Poe (sic) on any violations of criminal law."

But all five forensic specialists believe the medical evidence warranted a trial. All five said that the medical charts, toxicology and autopsy reports they reviewed indicate that deliberate overdoses the pain killer morphine and the sedative Versed led to the deaths of the nine patients.

"The primary and immediate cause of death for each of these patients was acute combined drug toxicity, specifically morphine and Versed," wrote Wecht. "The manner of death would be classified as homicide."

"Large doses of these drugs were present in patients and the administration of the drug was not documented," wrote James Young, the former chief coroner of the province of Ontario, Canada, who, like Wecht, once served as president of the American Academy of Forensic Sciences.

"Accidental overdoses would need to have occurred nine times between 12 noon and 3:30 p.m., all on one floor, to every patient who was left on the floor," Young wrote. " Again, it is noted that morphine was not ordered for seven of the patients and Versed was not ordered for any. Therefore it seems highly unlikely that nine patients died on the same floor on the same afternoon of accidental overdose."

Caplan wrote that there was no evidence any patient asked to be given assistance in dying, and no evidence that any consented to be given an overdose of medication to end their lives.

"In reviewing the facts and opinions, my conclusion is that the deaths of the nine persons at Memorial Medical Center in New Orleans are all cases of active euthanasia," Caplan wrote. "Each person died with massive doses of narcotic drugs in their bodies."

Dr. Frank Brescia, a Charleston, South Carolina, doctor specializing in palliative care, wrote that the patients were very ill and the deteriorating conditions in a hospital without air conditioning, electricity and running water contributed to the patients' declining health. Still, he wrote, those conditions did not kill them.

Brescia wrote, "I feel that the manner of death in these individuals, especially in four cases, obligates the legal process to consider them as homicides."

In fact, Brescia wrote in his report that the medical charts showed the patients were "stable, without an immediate or obvious threat of dying."

Dr. Michael Baden, a forensic pathologist from New York, also concluded that all nine patients died from drug overdoses.

"It is further my opinion that the circumstances surrounding these simultaneous deaths mandate a homicidal manner of death," Baden wrote.

Wecht was the first expert hired by Foti on the recommendation of New Orleans Parish Coroner Frank Minyard. When Jordan took over the case, he ordered Minyard to hire additional experts. Caplan was asked to review the work of Baden, Brescia, Wecht and Young.

Report: Decision made to administer lethal doses

In its executive summary report included with the forensic experts' findings, the attorney general's office paints a chilling picture of what its investigators say happened four days after the hurricane hit New Orleans.

The summary cites a number of people -- whose names are blacked out in the report -- as having offered statements through their attorneys and having sought immunity from prosecution.

The summary states that Pou told the nurse executive of Lifecare, the acute care facility on the seventh floor of the hospital that housed the nine patients, that "a decision had been made to administer lethal doses of morphine to Lifecare patients."

According to the report, none of the nine was a patient of Pou's and there was no indication she had talked to their doctors before seeing them on the day they died.

The attorney general's report also said that other medical personnel told Pou that one of the patients, Emmett Everett Sr., was conscious and alert. Everett was 61 years old, weighed almost 400 pounds and was confined to a wheelchair.

"Dr. Pou decided (patient name blacked out) could not be evacuated. He could not be taken out by boat because he was not ambulatory and Dr. Pou felt he was too heavy to be evacuated by helicopter," according to the report.

In a written statement, Pou's lawyer denied that the combination of morphine and Versed is a "lethal cocktail." In addition, Rick Simmons said Pou's own expert said it is well-known among scientists that blood levels of morphine are "greatly increased" in patients who have been dead for many days. Read Dr. Pou's response to attorney general (pdf)

Pou does not deny giving the patients drugs. In the days following Hurricane Katrina, floodwaters ran freely through the sweltering, pitch-black hospital, carrying human waste through its corridors, Pou told Newsweek.

Patients were moaning and crying in the halls; some were being fanned with slats of cardboard, others cooled off with dirty water and ice. Treatment was being administered under flashlights, Pou told the magazine.

"What you have to do when resources are limited, you have to save the people you know that you can save. And not everybody is going to survive those kind of conditions. And we knew that," Pou told Newsweek.

The patients on the seventh floor were among the sickest in the hospital, Pou said. Pou administered painkillers and sedatives "to help the patients that were having pain and sedate the patients who were anxious," she acknowledged.

"Basically what we're trying to do is help the patients. Let me tell you --God strike me dead -- what we were trying to do was help the patients," she told Newsweek. "Any medicines given were for comfort. If in doing so it hastened their deaths, then that's what happened. But this was not, 'I'm going to go to the seventh floor and murder some people.' We're here to help patients."

John DiGiulio, attorney for Landry, one of the nurses originally targeted by the state investigation, said he wasn't privy to the grand jury testimony. "But," he said, "I don't think any information was withheld from the grand jury."

DiGiulio said of his client and the circumstances in the hospital: "[The patients] were either dead or dying in the early days of Katrina. [Landry] was there to assist in giving comfort and care to the dying."

Eddie Castaing, attorney for Budo, the other nurse, said the state's experts' comments don't mean anything.

"The grand jury made its ruling of no true bill so it's not relevant," Castaing said, adding that he has no concerns about these documents.

"We could get 10 experts to say it's not homicide," he said. "It means nothing."

Brescia, one of the five medical experts, said the fate of Everett troubled him the most.

"This one case sort of stands out to you and says to you, 'Gee, I'm not sure what happened,' " Brescia said. "And that's what I said, this particular case, if you want to use the word suspicious or unclear or whatever word you want to use, I'm not sure why this patient is dead."

Family conducts its own investigation, says mom was poisoned

Family members of another one of the patients, Elaine Nelson, hired their own forensic expert to explore why the 90-year-old woman died. The report alarmed her son, Craig, a New Orleans lawyer.

"It showed that Mom had received on September 1 eight milligrams of morphine, which was four times the amount that she was prescribed by her doctor, and which was a lethal amount that was certainly enough to kill her," Nelson said.

Nelson said neither he nor his sister Kathy, a registered nurse who was with their mother after Katrina until guards ordered her to leave the hospital, were called before the grand jury. Their forensic expert wasn't called either.

Nelson has filed a lawsuit against the hospital owner and others. He said he refused a settlement offer because he wants the truth to come out, especially now that Jordan has closed the case. Nelson said he is disappointed in the way the grand jury was conducted.

"I think they'd want to hear as much evidence as possible to make a well-informed decision," he said.

But not everyone agrees. In early August, District Court Judge Calvin Johnson delayed a decision on whether to release more records in the case. Lawyers for some medical personnel and former hospital owner Tenet Healthcare Corporation are seeking to seal the records from the public. CNN, along with the New Orleans Times-Picayune, is seeking to get the records.

Johnson indicated he wasn't sure people should know what happened.

"What you presented to the grand jury room stayed in the grand jury room. On one level, I'll suggest no one should know. In a way, I don't want to know," the Times-Picayune quoted Johnson as telling the court.E-mail to a friend